Apr 26, 2014

Coffee cools, buildings crumble, eggs break and stars fizzle out in a universe that seems destined to degrade into a state of uniform drabness known as thermal equilibrium. The astronomer-philosopher Sir Arthur Eddington in 1927 cited the gradual dispersal of energy as evidence of an irreversible “arrow of time.”

But to the bafflement of generations of physicists, the arrow of time does not seem to follow from the underlying laws of physics, which work the same going forward in time as in reverse. By those laws, it seemed that if someone knew the paths of all the particles in the universe and flipped them around, energy would accumulate rather than disperse: Tepid coffee would spontaneously heat up, buildings would rise from their rubble and sunlight would slink back into the sun.

“In classical physics, we were struggling,” said Sandu Popescu, a professor of physics at the University of Bristol in the United Kingdom. “If I knew more, could I reverse the event, put together all the molecules of the egg that broke? Why am I relevant?”

Surely, he said, time’s arrow is not steered by human ignorance. And yet, since the birth of thermodynamics in the 1850s, the only known approach for calculating the spread of energy was to formulate statistical distributions of the unknown trajectories of particles, and show that, over time, the ignorance smeared things out.

Now, physicists are unmasking a more fundamental source for the arrow of time: Energy disperses and objects equilibrate, they say, because of the way elementary particles become intertwined when they interact — a strange effect called “quantum entanglement.”

“Finally, we can understand why a cup of coffee equilibrates in a room,” said Tony Short, a quantum physicist at Bristol. “Entanglement builds up between the state of the coffee cup and the state of the room.”

Popescu, Short and their colleagues Noah Linden and Andreas Winter reported the discovery in the journal Physical Review E in 2009, arguing that objects reach equilibrium, or a state of uniform energy distribution, within an infinite amount of time by becoming quantum mechanically entangled with their surroundings. Similar results by Peter Reimann of the University of Bielefeld in Germany appeared several months earlier in Physical Review Letters. Short and a collaborator strengthened the argument in 2012 by showing that entanglement causes equilibration within a finite time. And, in work that was posted on the scientific preprint site arXiv.org in February, two separate groups have taken the next step, calculating that most physical systems equilibrate rapidly, on time scales proportional to their size. “To show that it’s relevant to our actual physical world, the processes have to be happening on reasonable time scales,” Short said.

A watershed paper by Noah Linden, left, Sandu Popescu, Tony Short and
Andreas Winter (not pictured) in 2009 showed that entanglement causes
objects to evolve toward equilibrium. The generality of the proof is
“extraordinarily surprising,” Popescu says. “The fact that a system
reaches equilibrium is universal.” The paper triggered further research
on the role of entanglement in directing the arrow of time.

The tendency of coffee — and everything else — to reach equilibrium is “very intuitive,” said Nicolas Brunner, a quantum physicist at the University of Geneva. “But when it comes to explaining why it happens, this is the first time it has been derived on firm grounds by considering a microscopic theory.”

If the new line of research is correct, then the story of time’s arrow begins with the quantum mechanical idea that, deep down, nature is inherently uncertain. An elementary particle lacks definite physical properties and is defined only by probabilities of being in various states. For example, at a particular moment, a particle might have a 50 percent chance of spinning clockwise and a 50 percent chance of spinning counterclockwise. An experimentally tested theorem by the Northern Irish physicist John Bell says there is no “true” state of the particle; the probabilities are the only reality that can be ascribed to it.

Quantum uncertainty then gives rise to entanglement, the putative source of the arrow of time.

When two particles interact, they can no longer even be described by their own, independently evolving probabilities, called “pure states.” Instead, they become entangled components of a more complicated probability distribution that describes both particles together. It might dictate, for example, that the particles spin in opposite directions. The system as a whole is in a pure state, but the state of each individual particle is “mixed” with that of its acquaintance. The two could travel light-years apart, and the spin of each would remain correlated with that of the other, a feature Albert Einstein famously described as “spooky action at a distance.”

“Entanglement is in some sense the essence of quantum mechanics,” or the laws governing interactions on the subatomic scale, Brunner said. The phenomenon underlies quantum computing, quantum cryptography and quantum teleportation.

The idea that entanglement might explain the arrow of time first occurred to Seth Lloyd about 30 years ago, when he was a 23-year-old philosophy graduate student at Cambridge University with a Harvard physics degree. Lloyd realized that quantum uncertainty, and the way it spreads as particles become increasingly entangled, could replace human uncertainty in the old classical proofs as the true source of the arrow of time.

Seth Lloyd, now an MIT professor, came up with the idea that
entanglement might explain the arrow of time while he was in graduate
school at Cambridge University in the 1980s.

Using an obscure approach to quantum mechanics that treated units of information as its basic building blocks, Lloyd spent several years studying the evolution of particles in terms of shuffling 1s and 0s. He found that as the particles became increasingly entangled with one another, the information that originally described them (a “1” for clockwise spin and a “0” for counterclockwise, for example) would shift to describe the system of entangled particles as a whole. It was as though the particles gradually lost their individual autonomy and became pawns of the collective state. Eventually, the correlations contained all the information, and the individual particles contained none. At that point, Lloyd discovered, particles arrived at a state of equilibrium, and their states stopped changing, like coffee that has cooled to room temperature.

“What’s really going on is things are becoming more correlated with each other,” Lloyd recalls realizing. “The arrow of time is an arrow of increasing correlations.”

The idea, presented in his 1988 doctoral thesis, fell on deaf ears. When he submitted it to a journal, he was told that there was “no physics in this paper.” Quantum information theory “was profoundly unpopular” at the time, Lloyd said, and questions about time’s arrow “were for crackpots and Nobel laureates who have gone soft in the head.” he remembers one physicist telling him.

“I was darn close to driving a taxicab,” Lloyd said.

Advances in quantum computing have since turned quantum information theory into one of the most active branches of physics. Lloyd is now a professor at the Massachusetts Institute of Technology, recognized as one of the founders of the discipline, and his overlooked idea has resurfaced in a stronger form in the hands of the Bristol physicists. The newer proofs are more general, researchers say, and hold for virtually any quantum system.

“When Lloyd proposed the idea in his thesis, the world was not ready,” said Renato Renner, head of the Institute for Theoretical Physics at ETH Zurich. “No one understood it. Sometimes you have to have the idea at the right time.”

As a hot cup of coffee equilibrates with the surrounding air, coffee
particles (white) and air particles (brown) interact and become
entangled mixtures of brown and white states. After some time, most of
the particles in the coffee are correlated with air particles; the
coffee has reached thermal equilibrium.

In 2009, the Bristol group’s proof resonated with quantum information theorists, opening up new uses for their techniques. It showed that as objects interact with their surroundings — as the particles in a cup of coffee collide with the air, for example — information about their properties “leaks out and becomes smeared over the entire environment,” Popescu explained. This local information loss causes the state of the coffee to stagnate even as the pure state of the entire room continues to evolve. Except for rare, random fluctuations, he said, “its state stops changing in time.”

Consequently, a tepid cup of coffee does not spontaneously warm up. In principle, as the pure state of the room evolves, the coffee could suddenly become unmixed from the air and enter a pure state of its own. But there are so many more mixed states than pure states available to the coffee that this practically never happens — one would have to outlive the universe to witness it. This statistical unlikelihood gives time’s arrow the appearance of irreversibility. “Essentially entanglement opens a very large space for you,” Popescu said. “It’s like you are at the park and you start next to the gate, far from equilibrium. Then you enter and you have this enormous place and you get lost in it. And you never come back to the gate.”

In the new story of the arrow of time, it is the loss of information through quantum entanglement, rather than a subjective lack of human knowledge, that drives a cup of coffee into equilibrium with the surrounding room. The room eventually equilibrates with the outside environment, and the environment drifts even more slowly toward equilibrium with the rest of the universe. The giants of 19th century thermodynamics viewed this process as a gradual dispersal of energy that increases the overall entropy, or disorder, of the universe. Today, Lloyd, Popescu and others in their field see the arrow of time differently. In their view, information becomes increasingly diffuse, but it never disappears completely. So, they assert, although entropy increases locally, the overall entropy of the universe stays constant at zero.

“The universe as a whole is in a pure state,” Lloyd said. “But individual pieces of it, because they are entangled with the rest of the universe, are in mixtures.”

One aspect of time’s arrow remains unsolved. “There is nothing in these works to say why you started at the gate,” Popescu said, referring to the park analogy. “In other words, they don’t explain why the initial state of the universe was far from equilibrium.” He said this is a question about the nature of the Big Bang.

Despite the recent progress in calculating equilibration time scales, the new approach has yet to make headway as a tool for parsing the thermodynamic properties of specific things, like coffee, glass or exotic states of matter. (Several traditional thermodynamicists reported being only vaguely aware of the new approach.) “The thing is to find the criteria for which things behave like window glass and which things behave like a cup of tea,” Renner said. “I would see the new papers as a step in this direction, but much more needs to be done.”

Some researchers expressed doubt that this abstract approach to thermodynamics will ever be up to the task of addressing the “hard nitty-gritty of how specific observables behave,” as Lloyd put it. But the conceptual advance and new mathematical formalism is already helping researchers address theoretical questions about thermodynamics, such as the fundamental limits of quantum computers and even the ultimate fate of the universe.

“We’ve been thinking more and more about what we can do with quantum machines,” said Paul Skrzypczyk of the Institute of Photonic Sciences in Barcelona. “Given that a system is not yet at equilibrium, we want to get work out of it. How much useful work can we extract? How can I intervene to do something interesting?”

Sean Carroll, a theoretical cosmologist at the California Institute of Technology, is employing the new formalism in his latest work on time’s arrow in cosmology. “I’m interested in the ultra-long-term fate of cosmological space-times,” said Carroll, author of “From Eternity to Here: The Quest for the Ultimate Theory of Time.” “That’s a situation where we don’t really know all of the relevant laws of physics, so it makes sense to think on a very abstract level, which is why I found this basic quantum-mechanical treatment useful.”

Twenty-six years after Lloyd’s big idea about time’s arrow fell flat, he is pleased to be witnessing its rise and has been applying the ideas in recent work on the black hole information paradox. “I think now the consensus would be that there is physics in this,” he said.

An international team led by researchers at Uppsala University and Stockholm University reports a breakthrough on understanding the demographic history of Stone-Age humans. A genomic analysis of eleven Stone-Age human remains from Scandinavia revealed that expanding Stone-age farmers assimilated local hunter-gatherers and that the hunter-gatherers were historically in lower numbers than the farmers. The study is published today, ahead of print, in the journal Science.

The transition between a hunting-gathering lifestyle and a farming lifestyle has been debated for a century. As scientists learned to work with DNA from ancient human material, a complete new way to learn about the people in that period opened up. But even so, prehistoric population structure associated with the transition to an agricultural lifestyle in Europe remains poorly understood.

"For many of the most interesting questions, DNA-information from people today just doesn't cut it, the best way to learn about ancient history is to analyze direct data -- despite the challenges," says Dr. Pontus Skoglund of Uppsala University, now at Harvard University, and one of the lead authors of the study.

"We have generated genomic data from the largest number of ancient individuals" says Dr. Helena Malmström of Uppsala University and one of the lead authors. "The eleven Stone-Age human remains were between 5,000 and 7,000 years old and associated with hunter-gatherer or farmer life-styles" says Helena Malmström.

Anders Götherström, who led the Stockholm University team, is satisfied with the amount of DNA that they could retrieve.

"Not only were we able to generate DNA from several individuals, but we did get a lot of it. In some cases we got the equivalent of draft genomes. A population genomic study on this level with a material of this age has never been done before as far as I know."

The material used in the study is from mainland Scandinavia as well as from the Baltic island Gotland, and it comprises of hunter-gatherers from various time periods as well as early farmers.

Professor Mattias Jakobsson, who led the Uppsala University team, is intrigued by the results.

"Stone-Age hunter-gatherers had much lower genetic diversity than farmers. This suggests that Stone-Age foraging groups were in low numbers compared to farmers," says Mattias Jakobsson.

Jan Storå at Stockholm University shares Mattias' fascination.

"The low variation in the hunter gatherers may be related to oscillating living conditions likely affecting the population sizes of hunter-gatherers. One of the additional exciting results is the association of the Mesolithic individual to both the roughly contemporaneous individual from Spain but also the association to the Neolithic hunter-gatherers."

The study confirms that Stone-Age hunter-gatherers and farmers were genetically distinct and that migration spread farming practices across Europe, but the team was able to go even further by demonstrating that the Neolithic farmers had substantial admixture from hunter-gatherers. Surprisingly, the hunter-gatherers from the Baltic Sea displayed no evidence of introgression from farmers.

"We see clear evidence that people from hunter-gatherer groups were incorporated into farming groups as they expanded across Europe," says Pontus Skoglund. "This might be clues towards something that happened also when agriculture spread in other parts of the world."

Apr 25, 2014

If you're worried that you haven't spent enough time on the question of how a sloth can hang upside-down all the time without its slow-digesting stomach rendering its lungs useless, worry no more: Others have put in the time, and now there is an answer. It turns out, as it usually does, that evolution has played its part.

Sloths might be the least in-a-hurry creatures out there. They move sloooowly and spend the vast majority of their lives just hanging out, upside-down. They can sleep for up to 20 hours per day and in general do, well, absolutely nothing.

The problem is their digestive system isn't any faster than they are. They don't make waste very often and it can take forever for them to digest even the smallest meals. This results in a significant amount of their body weight taken up with stored waste, which should, but for an evolutionary adaptation, make it hard for the mellow creatures to use their lungs.

But researchers out of the University of Swansea working at the Costa Rica Sloth Sanctuary have discovered how the sloth can still breathe with all that weight pressing down. The creature has evolved abdominal adhesions that hold in place organs such as the liver and stomach. So the sloth can be upside-down and those organs don't come crushing down.

Thanks to the adhesion, sloths can conserve precious energy when they're in the mood to invert, and their breathing isn't impaired during their busy days. Neat trick!

New genetic evidence casts further doubt on the authenticity of a grisly French relic: a gourd long believed to be stained with the blood of Louis XVI.

Scientists sequenced the genome from dried blood inside the 200-year-old gourd and found that it didn't match with the DNA signatures of the king's ancestry, nor did it seem to carry the code for Louis XVI's celebrated traits, like his imposing height and blue eyes.

Deposed during the French Revolution, Louis XVI was executed by guillotine in January 1793, months before his wife, Marie Antoinette, fell victim to the Reign of Terror, too. According to legend, witnesses soaked up the king's blood with handkerchiefs after his beheading. An inscription on the elaborately decorated gourd claims the vessel held one of those bloody cloths. [See Photos of Louis XVI's Embalmed Head & Gourd]

Last year, a group of scientists compared the DNA signatures from blood found in the gourd with the DNA of three modern male relatives of Louis XVI from different branches of the Bourbon line. The Y chromosomes from the three men matched one another, but not the blood. This revelation, published in the European Journal of Human Genetics, sparked a new investigation.

"When the Y chromosome of three living Bourbons was decoded, and we saw that it did not match with the DNA recovered from the pumpkin in 2010, we decided to sequence the complete genome and to make a functional interpretation in order to see if the blood could actually belong to Louis XVI," Carles Lalueza-Fox, of the Spanish National Research Council (CSIC), said in a statement.

Based on their newly sequenced genome, Lalueza-Fox and colleagues think whomever the blood in the gourd belonged to didn't look like Louis XVI in terms of physical appearance or genealogical heritage.

Louis XVI was known for his towering stature; he may have stood over 6 feet (185?centimeters) tall. Though scientists do not entirely understand the genetic basis for height, Lalueza-Fox and colleagues wrote that the genome pieced together from the gourd blood was not consistent with that of a very tall person, but rather better matched someone with only slightly above-average height for the day. The king also had blue eyes, while the person who left their blood on the gourd more likely had brown eyes, the researchers say.

The mysterious abandonment of one of North America's first big cities may be linked to a massive Mississippi River flood 1,800 years ago, a new study finds.

In the bottom of an oxbow lake next to Cahokia, Ill., which was the most powerful and populous city north of Mexico in A.D. 1200, lie the buried remains of a flood that likely destroyed the crops and houses of more than 15,000 people. Researchers investigating pollen records of Cahokia's farming and deforestation discovered distinctive evidence of the flood: a silty layer 7.5 inches (19 centimeters) thick. The silt is dated to A.D. 1200, plus or minus 80 years, said Samuel Munoz, lead study author and a geographer at the University of Wisconsin-Madison.

The city wasn't completely abandoned until A.D. 1350, but the catastrophic flood could have shaken the confidence of the town, sited near modern-day St. Louis, Munoz said.

"I think the relationships between flooding and the decision to abandon the settlement are pretty complicated, but it's surprising and exciting to discover this flood happened right in the middle of a key turning point in Cahokia's history," Munoz said.

At its height, Cahokia sprawled over an area of about 6 square miles (16 square kilometers). Similar to modern-day New York City, Cahokia was an artistic and cultural center, where people brought in raw materials from across North America, and residents transformed them into exquisite goods.

Vast agricultural fields — where farmers grew crops such as corn, squash, sunflower, little barley and lambs quarters — surrounded the city. More than 200 earthen mounds rose from the city, many of which still loom over the landscape today.

Several years ago, Munoz set out to determine how Cahokia's residents shaped the local landscape; for instance, Munoz wanted to find out how much land was prairie and how much was forest, and how farming affected the region.

Cahokia's location near the confluence of major rivers made it a popular waypoint for some 2,000 years, according to Munoz's study, published April 10 in the journal Geology.

"There's not much that's natural about this place," Munoz told Live Science. "It's a great spot on the Mississippi, and it's really been affected by people for 2,000 years."

The grin has not been photoshopped onto this juvenile axolotl. What kind
of monster, after all, would impose emotions on an innocent salamander?

In medieval bestiaries, the salamander was a mythical creature of great power, capable of crawling leisurely through fire and even extinguishing it with its body. Leonardo da Vinci, in fact, believed that it even ate flames, though this is unlikely. Everyone knows fire is low on vitamins.

Unbeknownst to these Europeans, on the other side of the world there lives a salamander with powers far stranger than resistance to fire. It’s the axolotl of Mexico, a bizarre amphibian capable of regrowing limbs and even its spine with ease. Scientists have for decades struggled to unlock its regenerative secrets, all while our environmental meddling has nearly driven it to extinction.

Mexico City’s expansion, with its pollution and overfishing and incursions of invasive species, has virtually destroyed the salamander’s native lakes, which now exist as scant canals. A recent three-month survey there turned up zero axolotls, though a new survey currently in progress may have more luck.

But where the axolotl is actually flourishing is in labs, like that of biologist Randal Voss at the University of Kentucky, who studies the critter’s genetics. In particular, Voss looks at the dynamics of the salamander’s neoteny: its ability to indefinitely postpone metamorphosis–the type of transformation that turns tadpoles into frogs or caterpillars into butterflies–yet still reach sexual maturity. Thus the axolotl is the world’s most awkward-looking teenager.

While the axolotl’s natural hue is quite dark, almost black, scientists
can breed them into a range of colors. The one at center looks forlorn
because it lost its pigment sometime around birth, and has been unable
to find it.

Whereas other salamanders ditch their frilly external gills in favor of lungs and head for land, the axolotl plays it safe with the life aquatic. It not only holds on to the gills, it also develops lungs and can absorb oxygen through its skin.

So, why cling to youth? “The one thing that neotenic species have as an advantage is that if you don’t undergo this metamorphosis, you’re more likely to reproduce sooner,” said Voss. “You’re already one step ahead.”

An axolotl pair begins such pursuits with a sort of dance, nudging and pushing while the male releases pheromones (think of them as really effective colognes, à la Sex Panther) from his cloaca, a kind of all-purpose digestive and reproductive opening. As the female kicks these up, the male drops a rather odd-looking spermatophore.

Because the axolotl never truly metamorphoses, it retains its frilly
larval gills. It has lungs too. And can breathe through its skin.
Scientists therefore reckon that the axolotl is hopelessly addicted to
oxygen, more so than most critters.

“It looks just like a Hershey kiss,” said Voss. “It has a sperm packet on the very tip, and after laying that down he’ll walk up the body length, stop, and she’ll find it and sit down on it and break off the sperm cap. And that’s how she picks up the spermatophore.” Once fertilized, the female can lay more than 1,000 eggs, which hatch into larvae that will, alas, inevitably eat each other. (They should consider themselves lucky, though: Sand tiger shark young actually eat each other in the womb. I mean, at least give each other a chance.)

But the axolotls that emerge settle into life as adept bottom-dwelling predators. The axolotl hunts just like its distant cousins, the 6-foot giant salamanders of Asia, quickly firing open its maw to create a vacuum that pulls in small prey. And they can be quite voracious–in captivity axolotls feeding on clouds of brine shrimp have been known to nip off the limbs of their peers.

‘Tis But a Scratch

But like the Black Knight in Monty Python and the Holy Grail shrugging off the involuntary removal of his limbs, the axolotl can’t be bothered with mere flesh wounds. Incredibly, it can regrow entire arms, a tall order when you consider the complexity of such structures. Pretty magical, right?

An axolotl regrows an amputated limb over the course of just a month.
Or, if you scroll back up, slowly loses the arm. Perspective is very
important in science.

Not quite. According to biologist David Gardiner, whose lab at the University of California, Irvine is working to unravel the axolotl’s regenerative secrets, this critter isn’t that special after all. There are no unique tissues or structures making this possible. We humans have the same signaling molecules, as do fish and chickens, because long, long ago we shared a common ancestor that passed down these genes.

“We’re talking about very fundamental biological processes,” said Gardiner. “It’s not that they have special genes, it’s how they use those genes. It’s how they regulate them. That’s what’s special. And that’s how they regenerate and we don’t.”

It’s important to keep in mind that we humans regenerate just fine. Get a sunburn and your skin cells flake off to reveal new ones. Develop a scab and peel it away, and there’s your brand new tissue. And of course our livers readily regenerate, as poor Prometheus would attest if he wasn’t so busy having his plucked out by an eagle day in and day out.

The axolotl, however, doesn’t develop scar tissue at all. Instead, its unremarkable genes turn on or off in a remarkable sequence of steps that lead to the total regeneration of, say, an arm. Human regeneration actually begins to follow the same series of steps, but something hangs up along the way. Gardiner isn’t sure yet how many steps there are exactly, it could be 15 or 20 or 50, but he notes that we’re obviously failing somewhere early in the regeneration process.

“So if we make a choice somewhere around step three or four,” he said, “then the next 15 steps are irrelevant, because we do not go down that pathway. And we don’t know whether we can do them or not.”

“My sense is that we probably can do almost everything you need to do to regenerate,” he added. “Because we already do. I mean, most of the tissues regenerate–blood vessels and nerves and epithelial cells and muscle. The tissue that doesn’t regenerate is connective tissue, and that’s where we make scars.”

These connective tissue cells are what Gardiner focuses on in his axolotl research, because they’re the ones that manage the behavior of all other cells. “I like to think about it as the orchestra and the conductor,” he said. “Everything is there, but if there’s no conductor, the orchestra can’t make music.”

Gardiner thinks that it’s almost a certainty that humans will eventually be able to regenerate complex structures like limbs. It’s a long ways off though. We’re nowhere near to understanding how exactly the axolotl regenerates, much less figuring out how to give humans such powers. But say we do get there one day. Gardiner argues that what matters most with something like an arm is function, not form.

Apr 24, 2014

The earliest known pterodactyl was a tiny flying reptile that later evolved into giant beasts the size of airplanes.

The ancient creature was technically a "pterodacyloid pterosaur" that used to fly over northwest China when dinosaurs lived on land, according to a new study published in the latest issue of the journal Current Biology.

"This finding represents the earliest and most primitive pterodactyloid pterosaur, a flying reptile in a highly specialized group that includes the largest flying organisms," co-author Chris Liu, program director in the National Science Foundation’s Division of Earth Sciences, said in a press release.

"The research has extended the fossil record of pterodactyloids by at least five million years to the Middle-Upper Jurassic boundary about 163 million years ago."

The newly discovered animal, named Kryptodrakon progenitor, was found in a mudstone of the Shishugou Formation of northwest China. It had a wingspan of about 4.5 feet.

The name Kryptodrakon progenitor comes from Krypto (hidden) and drakon (serpent), referring to "Crouching Tiger, Hidden Dragon" filmed near where the species was discovered, and progenitor (ancestral or first-born), referring to its status as the earliest pterodactyloid, said co-author and paleontologist Brian Andres of the University of South Florida.

"He fills in a very important gap in the history of pterosaurs," Andres continued. "With him, they could walk and fly in whole new ways."

K. progenitor lived at what was then a flood plain. Its wings were narrow, a shape useful for swooping around marine environments. As its later relatives evolved, they developed broader wings to facilitate flying over land.

"Kryptodrakon is the second pterosaur species we've discovered in the Shishugou Formation and deepens our understanding of this unusually diverse Jurassic ecosystem," said co-author James Clark of the George Washington University Columbian College of Arts and Sciences.

He continued, "It is rare for small, delicate fossils to be preserved in Jurassic terrestrial deposits, and the Shishugou fauna is giving us a glimpse of what was living alongside the behemoths like Mamenchisaurus."

Mamenchisaurus was an enormous plant-eating dinosaur at the same place and time as the early pterodactyl. Its neck alone reached up to 31 feet, which must have been handy for reaching leaves and other edibles, not to mention intimidating carnivorous predators.

The authenticity of the "Gospel of Jesus's Wife" has been debated since the papyrus was revealed in 2012. Now, new information uncovered by Live Science raises doubts about the origins of the scrap of papyrus.

The gospel, written in the ancient Egyptian language Coptic, has made headlines ever since Harvard University professor Karen King announced its discovery. The business-card-size fragment contains the translated line "Jesus said to them, 'My wife …'" and also refers to a "Mary," possibly Mary Magdalene. If authentic, the papyrus suggests that some people believed in ancient times that Jesus and Mary Magdalene were married.

At the time of the discovery, King tentatively dated the papyrus to the fourth century A.D., saying it may be a copy of a gospel written in the second century in Greek.

Recently, several scientific tests published in the journal Harvard Theological Review have suggested the papyrus is authentic, but a number of scholars, including Brown University professor Leo Depuydt, dispute the papyrus's authenticity.

The document's current owner has insisted on remaining anonymous, and King has not disclosed the person's identity. However, in a recent Harvard Theological Review article, King published a contract provided by the current anonymous owner that King said indicates it was purchased, along with five other Coptic papyrus fragments, from a man named Hans-Ulrich Laukamp in November 1999 and that Laukamp had obtained it in 1963 from Potsdam in then-East Germany.

Provenance of a papyrus

In an effort to confirm the origins of the papyrus and discover its history, Live Science went searching for more information about Laukamp and his descendents, business partners or friends.

Our findings indicate that Laukamp was a co-owner of the now-defunct ACMB-American Corporation for Milling and Boreworks in Venice, Fla. Documents filed in Sarasota County, Fla., show that Laukamp was based in Germany at the time of his death in 2002 and that a man named René Ernest was named as the representative of his estate in Sarasota County.

In an exchange of emails in German, Ernest said that Laukamp did not collect antiquities, did not own this papyrus and, in fact, was living in West Berlin in 1963, so he couldn't have crossed the Berlin Wall into Potsdam. Laukamp, he said, was a toolmaker and had no interest in old things. In fact, Ernest was astonished to hear that Laukamp's name had been linked to this papyrus.

While the documents name him as the representative of Laukamp's estate in Sarasota County, the two men are not related, and Ernest did not receive an inheritance, Ernest said, adding that, as far as he knows, Laukamp had no children and has no living relatives.

Ernest did not respond to specific questions about how he and Laukamp came to know each other, but it is clear from documents naming Ernest as estate representative that Laukamp placed a great deal of trust in him; one dealing with Ernest and the estate dates to when Laukamp was still alive and has his signature.

Another acquaintance of Laukamp — Axel Herzsprung, who was also a co-owner of ACMB-American Corporation for Milling and Boreworks — told Live Science (in German in an email) that while Laukamp collected souvenirs on trips, he never heard of him having a papyrus. To his knowledge, Laukamp did not collect antiquities, Herzsprung said.

Live Science searched for other living relatives, checking for records in Sarasota County, and contacted a Laukamp family living in Florida, but they are unrelated. As far as we could tell, Ernest is correct, and Laukamp has no living relatives.

More questions

In the Harvard Theological Review article, King noted that she also received, from the current anonymous owner, a copy of a "typed and signed letter addressed to H. U. Laukamp" that dates to July 15, 1982, from Peter Munro, a now-deceased professor at the Freie University Berlin.

King wrote that the letter said that "a colleague, Professor Fecht, has identified one of Mr. Laukamp's papyri as having nine lines of writing, measuring approximately 110 by 80 mm, and containing text from the Gospel of John ..."

King noted that this document doesn't mention the Gospel of Jesus's wife explicitly. However, if Ernest and Herzsprung are correct, and Laukamp never collected antiquities, the question becomes: Why and how does this document exist? Munro died in 2009, and the "Professor Fecht" may be Gerhard Fecht, an Egyptology professor at the Freie University Berlin who passed away in 2006, King wrote in her article.

The arguments against the papyrus's authenticity by Depuydtand others are complex, but a key problem they cite is that the Coptic text is full of errors, to the extent that it is hard to believe that an ancient Coptic writer could have composed it.

It's not known whether scholars will ever be certain that the text is authentic. More information on its provenance may be found in the future.

A 240-square-mile (660 kilometer) iceberg, named B31, recently escaped into the open ocean from Pine Island Bay, Antarctica, announced NASA, which is monitoring the gargantuan chunk of ice.

Although the floating ice is roughly 10 times the size of Manhattan, it could be hard to track in the long darkness of the coming polar winter. British Antarctic Survey airplanes dropped 37 GPS tracking units onto the iceberg in January to follow it. NASA satellites also watch the iceberg’s movements from orbit.

Even with radar and warning systems, icebergs threaten modern ships with the same fate as the HMS Titanic. In 2007, the MS Explorer, an Antarctic cruise ship, sank after striking an iceberg near the South Shetland Islands, reported CBS News.

Shipping in the polar regions has increased in recent decades. At the same time, glaciers now calve more icebergs. Even small icebergs, known as growlers and bergy bits, threaten vessels.

“The growlers and bergy bits are difficult to detect by radar and satellite, yet are still capable of damaging or sinking a ship,” ocean physicist Peter Wadhams, of the University of Cambridge, told AccuWeather. “Since there are more icebergs and they are melting faster, we can expect a bigger population of growlers and berg bits, so more danger to shipping.”

By now, most of North America has thawed out from a brutal winter that introduced unhappy phrases such as "polar vortex" into the lexicon.

But some effects of the long-lasting, subfreezing temperatures are only now becoming apparent. One surprise was the discovery that starving rats in New York City had attacked the trees in urban parks for sustenance.

"With the deep snow and the cold winter, probably they didn't have access to the normal food supply and it was a lot colder this winter," Rich Hallett, a research ecologist with the U.S. Forest Service, told WNYC. "So they went after the trees."

The trees — which even in winter have some carbohydrates (mostly sucrose) in the vascular tissue beneath their bark — had been gnawed by rats all the way around the base of the trunk, a practice called "girdling" that usually kills a tree.Invasive pests' march halted

In addition to rats, a number of other pests had a rough time during the winter of 2013-2014, which broke records for cold from New England to the Midwest.

"I'm probably one of the few people that really roots for an extremely cold day, because I really do think it helps with some of the major insect problems that we have," Robert Venette, a biologist with the U.S. Forest Service in Minnesota, told NPR.

Invasive insects such as the emerald ash borer (Agrilus planipennis) and the hemlock wooly adelgid (Adelges tsugae), both of which have decimated native tree populations in the Northeast, may have had their march across America slowed or halted by extended periods of cold weather.

"Given that temps have gotten really cold, and not for one night but for an extended period, there's a tendency for a lot of people to hope for insect mortality," Deborah McCullough, a professor of entomology and forestry at Michigan State University in East Lansing, told the Capital News Service (CNS).

Other invasive pests vulnerable to subzero temperatures include the southern pine beetle (Dendroctonus frontalis), the brown marmorated stinkbug (Halyomorpha halys) and several species of ticks (Ixodes sp.), which can transmit Lyme disease and other illnesses.Sorry, no rat Armageddon

The population of Norway rats (Rattus norvegicus), whose numbers are almost wholly dependent on humans for food, may drop somewhat this year as a result of wintry blasts.

"If the snow gets really deep, and it's hard for young rats to jump across the snow and get to the food, then cold temperature might actually cause some mortality," urban ecologist Steve Sullivan of the Peggy Notebaert Nature Museumin Chicago told Fox News Chicago.

After the extinction of the dinosaurs, a balmy greenhouse Earth allowed rain forests to blanket Europe and North America. Geoscientists and paleontologists recently used fossil shells to provide evidence that even Antarctica enjoyed coastal California-like temperatures from 50 to 40 million years ago. This temperate polar climate warns of what can happen when carbon dioxide builds up in the atmosphere.

Antarctic temperatures may have hit 63 degrees Fahrenheit (17 C), with an average of 57 F (14 C). Those temperatures are close to average winter temperatures in San Francisco. Parts of the southern Pacific Ocean, where temperatures now hover around freezing, warmed to 72 F (22C), similar to the waters around Florida.

Rare forms of carbon and oxygen trapped in the fossilized shells of bivalves, like oysters and mussels, allowed geologists to estimate Antarctica’s ancient climate. Measurements of the ratios of those elemental forms, or isotopes, to more common isotopes allowed the climate calculations. The Proceedings of the National Academy of Sciences published the results.

The greenhouse effect caused the Antarctic warmth. During the early Eocene Epoch, 50 million years ago, carbon dioxide levels in the air reached 700 to 900 parts per million. That’s roughly double the present concentration of 400 parts per million in March 2014, according to records from the Mauna Loa Observatory in Hawaii.

During that warm period, lemur-like primates clambered through European rainforests and cypress trees grew on Ellesmere Island in the Arctic. The new study in PNAS shows that even the coldest continent, Antarctica, thaws out when greenhouse gases reach high enough levels in the atmosphere.

Apr 23, 2014

Finicky eaters usually do not survive mass extinction events, suggests a new study on prehistoric big cats.

Cougars, which will eat meat, guts, bones — the proverbial whole enchilada, survived the mass extinction event 12,000 years ago, while their finicky cousins the saber tooth cat and American lion bit the dust. The study, published in the journal Biology Letters, determined that eating habits probably saved cougars, and possibly jaguars too.

"Before the Late Pleistocene extinction, six species of large cats roamed the plains and forests of North America," co-author Larisa R.G. DeSantis, assistant professor of earth and environmental sciences at Vanderbilt University, said in a press release. "Only two -- the cougar and jaguar -- survived. The goal of our study was to examine the possibility that dietary factors can explain the cougar’s survival."

She and co-author Ryan Haupt of the University of Wyoming analyzed the teeth of ancient cougars, saber-tooth cats and American lions excavated from the famous La Brea Tar Pits in Los Angeles.

The researchers did this with a new technique called "dental microwear texture analysis." It uses a high-powered microscope to produce three-dimensional images of tooth surfaces. These images reveal tooth wear patterns that suggest how, and what, the animals often ate.

Chowing down on red meat, for example, produces small parallel scratches, while chomping on bones adds larger, deeper pits.

DeSantis and others previously found that the dental wear patterns of the extinct American lions closely resembled those of modern cheetahs, which are extremely finicky eaters that mostly consume tender meat and rarely gnaw on bones.

Saber-tooth cats were instead similar to African lions that chewed on both flesh and bone.

Some variation existed among the La Brea cougars, but many showed wear patterns closer to those of modern hyenas, which consume almost the entire body of their prey, bones and all.

A 2,000-year-old stonemason’s chisel that may have been used in the construction of Jerusalem’s Western Wall has been unearthed at the bottom of the structure along with a number of Second Temple-era objects, claims an Israeili archaeologist.

Some of the artifacts, which include a Roman sword, cooking vessels, a gold bell, coins and a ceramic seal, would suggest the Western Wall, a holy site for both Muslims and Jews, had not been built by King Herod at all.

Eli Shukron, an archaeologist working for the Israel Antiquities Authority (IAA), found the chisel last summer during a dig near a tunnel at the lower base of the Western Wall.

Also known as the Wailing Wall, the massive structure is venerated by Jews as the sole remnant of their Second Temple, destroyed by the Romans in 70 A.D. To the Muslims, the Western Wall is revered as the Wall of Buraq, the place where Muhammad tethered his winged horse Buraq after being transported from Mecca to Jerusalem.

Shukron, who has been working in the area with archaeologist Ronny Reich of the University of Haifa for the past 19 years, believes the chisel fell from a stonemason’s hand as he was working on scaffolding in the higher sections of the wall. The builder did not bother to get down and retrieve it.

“The chisel was found inside rubble of stone chips that fell from the stonemasons working on the rocks comprising the Western Wall,” Shukron told Israel’s daily Haaretz.

About 6 inches long, the metal tool features a flattened head, as a result of being repeatedly banged on rock.

“They were workers, human beings, who had tools. Today for the first time we can touch a chisel that belonged to one of them,” he added.

According to Haaretz, the IAA has not yet confirmed the finding, but Shukron trusts his findings.

“I have no doubt that it belongs to the time the Wall was built,” he said.

“We found it at the base of the Western Wall, about six meters (19.68 feet) below the main street of Jerusalem in the era of the Second Temple,” he added.

Commonly believed to have been part of King Herod’s massive expansion project on the Temple Mount, which included the Second Temple itself, the Western Wall may have not been built by the Bible’s bloodiest tyrant after all.

According to Shukron, the excavation revealed a number of coins beneath the wall which date decades after Herod’s death.

The coldest place on Earth is also one of the rare spots where a roiling lava lake offers a window into the heart of a volcano.

At Erebus volcano in Antarctica, a long-lived lava lake puffs steam and launches lava bombs at scientists who scale its slopes, hoping to unravel the mysteries of how volcanoes work. (Lava bombs are flying blobs of molten rock.)

"We think lava lakes are really the top of a magma chamber, so by studying lava lakes we can see what's happening in the guts of the volcano," said Philip Kyle, a volcanologist at New Mexico Tech in Socorro, who has visited Erebus since the late 1960s.

Erebus has been continuously active since as early as the 1970s. For more than 40 years, researchers like Kyle have climbed its 12,450-foot-tall (3,794 meters) peak during the brief summer, installing a battery of monitoring equipment that transforms Erebus into one of the most intensely watched volcanoes in the world.

In the early decades, scientists gathered just a few precious weeks' worth of data each summer at Erebus. Now, despite the harsh climate, everything from earthquake monitors to infrared cameras perch on the volcano year-round. Instruments also track the swelling and sinking of the volcano's surface, snooping on magma pulsing underground; listen to infrasound (sound below the range of human hearing); and sniff gases escaping into the air.

One of the remarkable discoveries to come from this long encampment is how regularly the lava lake huffs and churns, like a sleeping dragon. "I like to say Erebus is breathing, though I've been told off because Erebus can only breathe out," Kyle said.

Kyle's collaborator, Clive Oppenheimer, a volcanologist at the University of Cambridge, first noticed the lake's reliable pattern several years ago, from measuring its never-ending gas plume. The total amount of gas — mostly an equal measure of carbon dioxide and water, with a little sulfur dioxide and hydrogen chloride — rises and falls in a 10-minute-long cycle. The composition of the gas also switches on the same cycle.

But the brief summer research season meant scientists weren't sure if the phenomenon occurred only on their watch. Perhaps the dragon awoke in winter.

Now, with year-round equipment, Erebus investigators have proved the cycle persists year-round, varying between five and 18 minutes since 2004, according to a study to be published June 2014 in the journal Earth and Planetary Science Letters.

"The behavior has stayed remarkably constant, which is actually quite unusual for volcanoes," said Nial Peters, lead study author and a geophysicist at the University of Cambridge in the United Kingdom.

The new study also reports other intriguing behavior in the bubbling lake. For instance, the lava heaves in concert with its 10-minute gas cycle, its surface rising and falling by about 6 to 10 feet (2 to 3 m), Peters said. And lava cooling on the lake surface cracks and flows outward at a speed that matches the fluctuating gases. "Think of the lake as a bowl sitting on top of a pipe, and as fresh batches of magma come up into the bottom they rise up and spread out," Peters told Live Science's Our Amazing Planet. "That's what we see in the velocity flow outward from the center of the lake. It looks like a thick, treacly liquid, which is gradually convecting."

Lava lakes are rare — there are only four long-lived lakes on Earth, because the volcano must continuously supply lava to the surface. There are lakes at Erebus, Hawaii's Kilauea volcano, Ethiopia's Erta Ale volcano, and Nyiragongo volcano in the Democratic Republic of the Congo.

Erebus volcano's magma is a rare type called phonolite, up to 100 times more viscous than the basalt at Kilauea in Hawaii and Erta Ale in Ethiopia. Though Erebus is the only active volcano with phonolite lava, its twin is Kilimanjaro in the East African Rift, Kyle said. Both are steep-sided, cone-shaped phonolite volcanoes rising from rifts, where the Earth's crust is stretching apart. Looming up from Ross Island, Erebus is visible from McMurdo research station and New Zealand's Scott Base.

The long-term observations at Erebus volcano's lava lake are among the only rigorous studies of these valuable windows into magmatic systems, said Matt Patrick, a volcanologist with the U.S. Geological Survey's Hawaii Volcano Observatory, who was not involved in the study.

"The Peters paper represents a big step in understanding active lava lakes, in large part due to the uniquely detailed observations they have made of the lava lake activity," Patrick said.

With their bounty of data, the members of the Erebus team are now moving toward their next big goal: explaining how the volcano works.

"That's the $64,000 dollar question," Kyle said of the oddly predictable plumbing.

Here's what might cause the steady exhalations. Think of blobs rising and falling in a lava lamp. Now put those blobs in an underground pipe that feeds the lava lake from a deeply buried magma chamber. Lava moves up and down the pipe — a flow and counterflow similar to a lava lamp, according to a model in a separate study to be published in the same issue of the journal Earth and Planetary Science Letters.

"The physics of what's going on are fairly different, but it's an easy analogy," said Peters, who is co-author on the "lava lamp" study. "Batches of fresh magma come in as blobs, not as a continuous stream."

But just like a real body, this "breathing" comes from a different part of the volcano than its burping eruptions. Erebus erupts when a large gas bubble emerges and bursts in the lake, splattering lava on the surrounding slopes. Some of the volcano's lava bombs are nearly bus-size.

At Erebus, these belches have a different composition than the gases that ebb and flow every 10 minutes, researchers discovered. The investigators think this difference means that the bomb-launching bubbles come from deeper in the volcano.

"It looks like the two behaviors are very decoupled from each other," Peters said. The gas cycling continues even when eruptions suddenly lower the lava lake level, he noted.

Computer modeling of the upper and lower volcanic plumbing will help explain this strange set of behaviors and provide insight into the inner workings of other volcanoes, Peters said.

Electrical pulses delivered from a cochlear implant to the inner ear can be used to regrow auditory nerves to both enhance hearing and deliver gene therapy that could treat everything from Parkinson’s disease to depression, according to new research published today in Science Translational Medicine.

“Our work has implications far beyond hearing disorders,” said study co-author Matthias Klugmann from the University of New South Wales Translational Neuroscience Facility research team. “Gene therapy has been suggested as a treatment concept even for devastating neurological conditions and our technology provides a novel platform for safe and efficient gene transfer into tissues as delicate as the brain.”

Knowing that auditory nerve endings regenerate if certain proteins are present, but that drugs and viral-based gene therapy couldn’t provide a safe method of delivery, researchers started looking at cochlear implants as a method of delivery.

The team found that electrical pulses delivered from the implant could transport the DNA to cells close to the implanted electrodes. Those cells would then produce those key proteins, called neurotrophins, that stimulate the regeneration.

The procedure, which took five years to develop, would help people who rely on cochlear implants to hear be able to differentiate a broader tonal range of sound, which would likely allow them to appreciate music.

“People with cochlear implants do well with understanding speech, but their perception of pitch can be poor, so they often miss out on the joy of music,” said researcher Gary Housley.

The electrical pulses could be administered during the implant procedure.

Apr 22, 2014

Geoscientists have identified a chunk of Africa stuck onto the southeastern United States.

A long mysterious zone of unusual magnetism that stretches from Alabama through Georgia and offshore to the North Carolina coast appears to be the suture between ancient rocks that formed when parts of Africa and North America were pressed together 250 million years ago. If so, Africa could have left a lot more behind in the American southeast when the conjoined continents rifted apart and formed the Atlantic Ocean.

"There are some large faults in the magnetic data," said geologist Robert Hatcher of the University of Tennessee in Knoxville, regarding what is called the Brunswick Magnetic Anomaly and other magnetic features in the region. "They have not been active for a very long time. They are strike-slip faults like the San Andreas today. But there's also younger fall with opposite direction."

The faults appear to be the remains of the collision and then messy divorce of Africa and North America.

"There was an attempt to rip away Florida and southern Georgia," said Hatcher. "So you have a failed rift there. We know there's a suture there between African crust and newer crust from the Appalachians. There are pieces of crust that started in Africa."

A rift is what happens when the crust is pulled apart. When that happened 200 million years ago, 50 million years after African and North America collided, it appears to have started near the old collision zone, but then shifted to weaker crust to the east.

That rift zone split open and caused volcanic eruptions which created new oceanic crust -- what is today the crust of the Earth under the Atlantic Ocean. The rifting continues today at what's called the Mid-Atlantic Ridge.

"The age of the suture zone is believed to be about 250 million years old, but that's not very well constrained," said geologist Elias Parker, Jr., of the University of Georgia in Athens. He published a paper reviewing what's known about the Brunswick Magnetic Anomaly in the latest issue of GSA Today.

The big challenge in sorting out the history of the southeast U.S. is that there are intriguing magnetic signals, as well as gravimetric measurements, but there is not enough deep borehole studies or seismic data to confirm the faults and the proposed scenarios.

A satellite photograph has many people wondering whether the elusive Loch Ness monster might have been photographed from space.

The image seems to show a strange, ghostly oval shape with trailing white tendrils either on the surface, or just below the surface, of Scotland's famous Loch Ness. The images were taken years ago but re-surfaced last week when the story was picked up by British newspapers.

Monster-hunters debated the new evidence, but soon several websites debunked the "Nessie" photo, including www.southernfriedscience.com, DoubtfulNews.com and www.metabunk.org, which offered clear explanations for how the image was created. The conclusion: The image of the Loch Ness Monster is simply a boat wake.

In fact, the distinctive wake pattern exactly matches that created by other boats, both on Ness and in other lakes. The satellite image is not a single image, as many assume, but instead a composite of several different images, each with a different contrast; this helped create the illusion of a creature.

So if the latest Loch Ness monster photo turned out to simply be a boat, why did it look so mysterious?

Why satellite images mislead

While early proclamations of Nessie having been found by a satellite have likely caused some red faces, we shouldn't be too quick to judge those who saw a monster where none existed. The idea that a satellite could capture an image of a giant monster is not far-fetched. Many lake monsters and sea serpents are reported to be 50 feet (15 meters) or longer, and surface regularly where they are seen.

If armchair investigators are up to the task, they could monitor monster-inhabited lakes such as Scotland's Loch Ness, Canada's Lake Okanagan and America's Lake Champlain using satellite technology. Monster buffs don't need to dip their toes into cold lakes or brave the wilderness to search for their quarry; they can scan a dozen square miles over a cup of hot coffee at their leisure.

In their book "Remote Sensing and Image Interpretation" (Wiley, 2007), authors Thomas Lillesand, Ralph Kiefer and Jonathan Chipman explain why satellite images can easily mislead the public: "Although most individuals have had substantial experience in interpreting 'conventional' photographs in their daily lives, the interpretation of aerial and space images often departs from everyday image interpretation in three important aspects: 1) the portrayal of features from an overhead, often unfamiliar, perspective; 2) the frequent use of wavelengths outside of the visible portion of the spectrum; and 3) the depiction of the Earth's surface at unfamiliar scales and resolutions."

Indeed, biologist Andrew David Thaler noted several of these issues in his Southern Fried Science blog about the latest Nessie photo: "Satellite images aren't taken in real time. The photographs in question were taken in January 2005 ... Satellites travel along an orbital path, taking pictures that are then stitched together stitched photos aren't perfect. For example, if one picture has a boat that's totally washed out (like almost every boat is when photographed from space) and another picture is just blue water, then you'll be left with the ghostly blue outline of a boat, which is clearly visible on the 'Nessie' picture." Case closed.

This is, of course, not the first time that a strange satellite image has caused controversy.

In 2011, people reviewing images on Google Maps spotted a tangle of mysterious, connected white lines in the Chinese desert. The strange images spurred a furor on the Web, where amateur sleuths offered learned (and not-so-learned) opinions about their function, ranging from UFO landing strips to top-secret military bunkers. The lines were eventually identified as a grid used to calibrate Chinese spy satellites.

As satellite images become more common, these sorts of "mysterious" photographs will also likely become more common unless the public becomes more educated about satellite imagery. After all, only photographs that are ambiguous and mysterious enough will come to the public's attention. If a photograph is crystal clear and unambiguous, no one will pay attention to it, because its identity is obvious.

On the other hand if a photograph is too ambiguous, it is likely to be ignored or deleted as an obvious mistake of such poor quality that it's worthless — it's the same reason we don't see the worst photos that people take with their cellphones, because they're soon deleted. For an image to be "mysterious" it needs to fall into that Goldilocks zone of being just clear enough to give an idea of what it might be, but not clear enough to actually tell what it is.

Modern humans may have dispersed in more than one wave of migration out of Africa, and they may have done so earlier than scientists had long thought, researchers now say.

Modern humans first arose between 100,000 and 200,000 years ago in Africa. But when and how the modern human lineage then dispersed out of Africa has long been controversial.

Scientists have suggested the exodus from Africa started between 40,000 and 70,000 years ago. However, stone artifacts dating to at least 100,000 years ago that were recently uncovered in the Arabian Desert suggested that modern humans might have begun their march across the globe earlier than once suspected.

To help solve this mystery, Katerina Harvati, a paleoanthropologist at the University of Tübingen in Germany, and her colleagues tested four competing out-of-Africa models. Two models involved a single dispersal — one involved a route northward, up the Nile River valley and then eastward across the northern end of the Arabian Peninsula into Asia; the other involved a "beachcomber" route along the southern coast of the Arabian Peninsula into Asia. Two other models involved multiple dispersals, with both models involving routes along the northern and southern ends of the Arabian Peninsula — one involved connections and gene flow between these routes, and the other did not.

The investigators used these models to predict how much the genes and skull measurements of different groups in Africa, Asia and Australia might have diverged from one another given how separated they were by space and time. Then, the researchers compared these predictions with actual gene and skull data from 10 African, Asian and Australian human populations.

The researchers found that both the genetic and skull data supported a multiple-dispersal model involving several migrations.

"It is really exciting that our results point to the possibility of a multiple-dispersals model of modern humans out of Africa," Harvati said. "A multiple-dispersals scenario, with earlier modern humans leaving Africa as early as 130,000 before present, can perhaps account for part of the morphological and genetic patterns that we see among modern human populations."

The first wave of migrations probably followed the southern coast of the Arabian Peninsula as early as 130,000 years ago to Australia and the west Pacific region, while the second wave traveled along the northern route about 50,000 years ago, the researchers said. These waves of migration appear relatively isolated from each other.

"Australian Aborigines, Papuans and Melanesians were relatively isolated after the early dispersal along the southern route," study lead author Hugo Reyes-Centeno, of the University of Tübingen, said in a statement. Other Asian populations apparently descended from members of the later northern wave of migration, the researchers said.

The delay between these waves of migration could be due to ancient environmental factors, "specifically climatic conditions that might have impeded the crossing of the Arabian Peninsula, such as desert conditions," Harvati said.

Ancient environmental factors might not only have prevented migrations, but also spurred them, Havarti said.

"For example, the documentation of severe droughts throughout eastern Africa between about 75,000 to 135,000 years ago could have encouraged a dispersal into other parts of Africa as well as outside of the continent," Harvati said. "More favorable conditions within Africa could have limited migrations out of the continent between 75,000 to 50,000 years ago."

The researchers cautioned that interbreeding between modern humans and other lineages of humans might influence the results of this new study. For example, instances of interbreeding with the now-extinct Denisovan lineage might have introduced ancient genes into certain modern human groups, perhaps making them look as if they left Africa earlier than they actually did.

"Our study did not specifically test for hybridization with archaic humans, and, of course, it is possible that such admixture could contribute to our results," Harvati said. "We feel, however, that the very low levels of admixture that have been proposed are not sufficient to drive our findings."

The researchers said continued fieldwork and genetic advancements might help confirm this model of multiple, relatively isolated waves of migration.

"The story of human evolution tends to be simplified," Harvati said. "However, more complex models, such as multiple dispersals versus a single dispersal out of Africa, gain strength as more data and new methods become available."

Neanderthals were remarkably less genetically diverse than modern humans, with Neanderthal populations typically smaller and more isolated, researchers say.

Although Neanderthals underwent more genetic changes involving their skeletons, they had fewer such changes in behavior and pigmentation, scientists added.

Modern humans are the only humans alive today, but Earth was once home to a variety of other human lineages. The Neanderthals were once the closest relatives of modern humans, with the common ancestors of modern humans and Neanderthals divergingbetween 550,000 and 765,000 years ago.

Neanderthals and modern humans later interbred -- nowadays, about 1.5 to 2.1 percent of DNA of people outside Africa is Neanderthal in origin.

Researchers first sequenced the Neanderthal genome in 2010. "One of the next goals was obviously to begin to explore the variation among Neanderthals," said study author Svante Pääbo, an evolutionary geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

Pääbo and his colleagues analyzed three Neanderthal genomes. One came from a 49,000-year-old specimen from Spain; another from a 44,000-year-old specimen from Croatia; and one from a Siberian specimen at least 50,000 years old.

"For the first time we begin to get a detailed picture of genetic variation among Neanderthals," Pääbo told Live Science.

The scientists found that Neanderthals "had even less variation than present-day humans, who are already known to have less than chimpanzees and most other apes," Pääbo said. "The amount of genetic diversity in the Neanderthals was about a quarter of that in Africans today, and about a third of that in Europeans or Asians."

To pinpoint why Neanderthals might have been less genetically diverse, the researchers focused on 17,367 genes that encoded instructions for generating proteins. They concentrated on mutations that changed what amino acids went into those proteins. Such mutations have a good chance of altering the structure or function of those proteins.

Although mutations that change the amino acid makeup of proteins can have benefits, more often than not, they have detrimental effects. One should expectnatural selection to weed out these mutations over time, as anyone bearing them is probably less fit and thus not as likely to survive to reproduce.

However, such mutations can accumulate in small, isolated populations, since those groups have fewer normal versions of those genes in their gene pools to replace any mutant genes.

The investigators found Neanderthals carried more copies of mutations that would alter the amino acid makeup of proteins than modern humans possess. This suggests that Neanderthal populations across Eurasia were likely small and isolated.

"Neanderthals seem to have been few in numbers either over a long time or for some periods," Pääbo said. "There is also an indication that they have been subdivided in populations that had little contact with each other."

The fact that Neanderthals carried more copies of potentially detrimental mutations did not necessarily contribute to their extinction, said lead study author Sergi Castellano, at the Max Planck Institute for Evolutionary Anthropology. "No claim should be made that this is related to their extinction," Castellano told Live Science.

The researchers also found skeleton genes changed more than expected within the Neanderthal lineage.

"For example, genes that affect the curvature of the spine have changed in Neanderthals," Pääbo said. "This fits with how their skeletons have changed quite drastically during their evolution."

On the other hand, genes involved with pigmentation and behavior changed more in the modern human lineage.

Apr 21, 2014

Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists exploring large fields of impact glass in Argentina suggest that what happened on Earth might well have happened on Mars millions of years ago. Martian impact glass could hold traces of organic compounds.

Asteroid and comet impacts can cause widespread ecological havoc, killing off plants and animals on regional or even global scales. But new research from Brown University shows that impacts can also preserve the signatures of ancient life at the time of an impact.

A research team led by Brown geologist Pete Schultz has found fragments of leaves and preserved organic compounds lodged inside glass created by a several ancient impacts in Argentina. The material could provide a snapshot of environmental conditions at the time of those impacts. The find also suggests that impact glasses could be a good place to look for signs of ancient life on Mars.

The work is published in the latest issue of Geology Magazine.

The scorching heat produced by asteroid or comet impacts can melt tons of soil and rock, some of which forms glass as it cools. The soil of eastern Argentina, south of Buenos Aires, is rife with impact glass created by at least seven different impacts that occurred between 6,000 and 9 million years ago, according to Schultz. One of those impacts, dated to around 3 million years ago, coincides with the disappearance of 35 animal genera, as reported in the journal Science a few years back.

"We know these were major impacts because of how far the glass is distributed and how big the chunks are," Schultz said. "These glasses are present in different layers of sediment throughout an area about the size of Texas."

Within glass associated with two of those impacts -- one from 3 million years ago and one from 9 million years ago -- Schultz and his colleagues found exquisitely preserved plant matter. "These glasses preserve plant morphology from macro features all the way down to the micron scale," Schultz said. "It's really remarkable."

The glass samples contain centimeter-size leaf fragments, including intact structures like papillae, tiny bumps that line leaf surfaces. Bundles of vein-like structures found in several samples are very similar to modern pampas grass, a species common to that region of Argentina.

Chemical analysis of the samples also revealed the presence of organic hydrocarbons, the chemical signatures of living matter.

To understand how these structures and compounds could have been preserved, Schultz and his colleagues tried to replicate that preservation in the lab. They mixed pulverized impact glass with fragments of pampas grass leaves and heated the mixture at various temperatures for various amounts of time. The experiments showed that plant material was preserved when the samples were quickly heated to above 1,500 degrees Celsius.

It appears, Schultz says, that water in the exterior layers of the leaves insulates the inside layers, allowing them to stay intact. "The outside of the leaves takes it for the interior," he said. "It's a little like deep frying. The outside fries up quickly but the inside takes much longer to cook."Implications for Mars

If impact glass can preserve the signatures of life on Earth, it stands to reason that it could do the same on Mars, Schultz says. And the soil conditions in Argentina that contributed to the preservation of samples in this study are not unlike soils found on Mars.

The Pampas region of Argentina is covered with thick layers of windblown sediment called loess. Schultz believes that when an object impacts this sediment, globs of melted material roll out from the edge of the impact area like molten snowballs. As they roll, they collect material from the ground and cool quickly -- the dynamics that the lab experiments showed were important for preservation. After the impact, those glasses are slowly covered over as dust continues to accumulate. That helps to preserve both the glasses and the stowaways within them for long periods -- in the Argentine case, for millions of years.

Harvard neuroscientists have made a discovery that turns 160 years of neuroanatomy on its head.

Myelin, the electrical insulating material long known to be essential for the fast transmission of impulses along the axons of nerve cells, is not as ubiquitous as thought, according to a new work lead by Professor Paola Arlotta of the Harvard Stem Cell Institute (HSCI) and the University's Department of Stem Cell and Regenerative Biology, in collaboration with Professor Jeff Lichtman, of Harvard's Department of Molecular and Cellular Biology.

"Myelin is a relatively recent invention during evolution," says Arlotta. "It's thought that myelin allowed the brain to communicate really fast to the far reaches of the body, and that it has endowed the brain with the capacity to compute higher level functions." In fact, loss of myelin is a feature of a number of devastating diseases, including multiple sclerosis and schizophrenia.

But the new research shows that despite myelin essential roles in the brain, "some of the most evolved, most complex neurons of the nervous system have less myelin than older, more ancestral ones" Arlotta, co-director of the HSCI neuroscience program, says.

What this means, Arlotta says, is that the higher in the cerebral cortex one looks -- the closer to the top of the brain, which is its most evolved region -- the less myelin one finds. Not only that, but "neurons in this part of the brain display a brand new way of positioning myelin along their axons that has not been previously seen. They have 'intermittent myelin' with long axon tracts that lack myelin interspersed among myelin-rich segments.

Arlotta continues: "contrary to the common assumptions that neurons use a universal profile of myelin distribution on their axons, the work indicate that different neurons choose to myelinate their axons differently. In classic neurobiology textbooks myelin is represented on axons as a sequence of myelinated segments separated by very short nodes that lack myelin. This distribution of myelin was tacitly assumed to be always the same, on every neuron, from the beginning to the end of the axon. This new work finds this not to be the case."

The results of the research by Arlotta and post doctoral fellow Giulio Srubek Tomassy, the first author on the report, are published in the latest edition of Science, the journal of the American Association for the Advancement of Science.

The paper is accompanied by a "Perspective" by R. Douglas Fields, of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, at the National Institutes of Health, who says that Arlotta and Tomassy's findings raise important questions about the purpose of myelin, "are likely to spark new concepts about how information is transmitted and integrated in the brain."

Arlotta and Tomassy collaborated closely on the new work with postdoctoral fellow Daniel Berger of the Lichtman group, which generated one of the two massive electron microscopy data bases that made the work possible.

"The fact that it is the most evolved neurons, the ones that have expanded dramatically in humans, suggests that what we're seeing might be the "future." As neuronal diversity increases and the brain needs to process more and more complex information, neurons change the way they use myelin to "achieve" more," says Arlotta.

Apr 20, 2014

There's no story in the Bible about a long-eared, cotton-tailed creature known as the Easter Bunny. Neither is there a passage about young children painting eggs or hunting for baskets overflowing with scrumptious Easter goodies.

And real rabbits certainly don't lay eggs.

Why are these traditions so ingrained in Easter Sunday? And what do they have to do with the resurrection of Jesus?

Well, to be frank, nothing.

Bunnies, eggs, Easter gifts and fluffy, yellow chicks in gardening hats all stem from pagan roots. These tropes were incorporated into the celebration of Easter separately from the Christian tradition of honoring the day Jesus Christ rose from the dead.

According to the University of Florida's Center for Children's Literature and Culture, the origin of the celebration — and the origin of the Easter Bunny — can be traced back to 13th-century, pre-Christian Germany, when people worshiped several gods and goddesses. The Teutonic deity Eostra was the goddess of spring and fertility, and feasts were held in her honor on the Vernal Equinox. Her symbol was the rabbit because of the animal’s high reproduction rate.

Spring also symbolized new life and rebirth; eggs were an ancient symbol of fertility. According to History.com, Easter eggs represent Jesus' resurrection. However, this association came much later when Roman Catholicism became the dominant religion in Germany in the 15th century and merged with already ingrained pagan beliefs.

The first Easter Bunny legend was documented in the 1500s. By 1680, the first story about a rabbit laying eggs and hiding them in a garden was published. These legends were brought to the United States in the 1700s, when German immigrants settled in Pennsylvania Dutch country, according to the Center for Children's Literature and Culture.

The tradition of making nests for the rabbit to lay its eggs in soon followed. Eventually, nests became decorated baskets and colorful eggs were swapped for candy, treats and other small gifts.

Is the Bible Fact or Fiction? The question has been debated for centuries by archaeologists, religious scholars and historians. So far, no definitive answer has been given. Science and archaeological discoveries have supported the Bible in some instances while refuting many of its most popular tales.

Read on to discover some of the more contentious issues in the Bible that may or may not stand up to historic and scientific scrutiny.Camels in the Bible

Abraham's Journey from Ur to Canaan, József Molnár, 1850.

Camels play a central role in Genesis and are mentioned as pack animals in the biblical stories of Abraham, Joseph and Jacob. But according to newly published research by Tel Aviv University based on radiocarbon dating and evidence unearthed in excavations, camels were not domesticated in the Land of Israel until the 10th century BC -- several centuries after the time they appear in the Bible.

"In addition to challenging the Bible's historicity, this anachronism is direct proof that the text was compiled well after the events it describes," the university said in a statement.

However, several scholars believe the study, by archaeologists Erez Ben-Yosef and Lidar Sapir-Hen, adds little to our knowledge.

"We have known about this camel anachronism for over a century now from site analysis. The Hebrews were donkey people hugging the coastlines and water routes, not camel people," Robert Eisenman, professor of Middle East religions, archaeology, and Islamic law and director of the Institute for the Study of Judaeo-Christian Origins at California State University Long Beach, told Discovery News.

Eisenman contends that many of these materials are based on oral tradition.

"So, though they might have been put into writing later, that doesn't mean they were not originally created much earlier,” he said.

Adam and Eve

A number of studies have questioned the historicity of the Bible's first couple.

The fossil record indicates that humans did not appear suddenly, but evolved gradually over the course of six million years.

However, “Y-chromosome Adam” and “mitochondrial Eve,” the two individuals who passed down a portion of their genomes to the vast expanse of humanity, may have lived around the same time.

According to a recent, extensive genetic study by Stanford University School of Medicine, the man lived between 120,000 and 156,000 years ago, and the woman lived between 99,000 and 148,000 years ago.

Genetic Adam and Eve

However, attempts to reconcile genetics with Genesis are unlikely to succeed.

“Despite the Adam and Eve monikers, which evoke a single couple whose children peopled the world, it is extremely unlikely that the male and female most recent common ancestors were exact contemporaries,” Stanford University stated.

Indeed, they weren’t the only man and woman alive at the time, or the only people to have present-day offspring.

“These two individuals simply had the good fortune of successfully passing on specific portions of their DNA -- from the man, the Y chromosome; from the woman, the mitochondrial genome -- through the millennia to most of us, while the corresponding sequences of others have largely died out,” the university said.

The Great Flood

Hundreds of archaeological excavations have attempted to find evidence of an apocalyptic flood such as is described in both the Bible and the Epic of Gilgamesh, but none succeeded. There is no trace anywhere on the archaeological record of a devastating global flood.

Likewise, expeditions to find the ark Noah built to save himself, his family and pairs of animals from the great deluge left archaeologists at a dead end.

According to Genesis, after the flood killed nearly everything on Earth, the ark came to rest on the mountains of Ararat in Eastern Turkey.

The Ark

The cuneiform script on this 3,700-year-old clay tablet reveals that the ark was round.

Biblical creationists imagined Noah's Ark like a large, box-like vessel similar to the version shown in Aronofksy's epic movie. Other designs added a sloping roof and matched the ships of the day, from square-rigged caravels to long vessels with pointy bows.

Further representation set the standard for children's story books, depicting the vessel as a large house on a boat, with a pair of giraffes sticking out of the roof.

But according to a recently decoded cuneiform script on a 3,700-year-old clay tablet, the original ark was a giant round vessel.

"The Babylonians of around 1750 believed the ark in the flood story was a giant version of the type of coracle that they actually used on the rivers," Irving Finkel, a British Museum curator who translated the script and the author of "The Ark before Noah: Decoding the Story of the Flood," told Discovery News.

Indeed, a huge waterproof coracle would never sink. According to Elizabeth Stone, an anthropology professor at New York's Stony Brook University, such a boat makes perfect sense in Mesopotamia, where round boats are likely to have been used on the Tigris and Euphrates rivers.The Exodus

There is no proof that the Exodus and the related miracles -- the devastating plagues, the burning bush, the parted sea, the manna in the wilderness -- really occurred.

While turning up artifacts from as far back as the late Stone Age, excavations in the Sinai did not produce a single piece of evidence for the Israelites' 40-year wandering in the desert.

Biblical scholars today widely agree that there was never any mass migration of the proportions described in the Bible. It is estimated the diaspora would have numbered some 2 million people out of an entire Egyptian population in 1250 BC of around 3 to 3.5 million.Moses

Revered by the world's three main monotheistic religions -- Judaism, Islam and Christianity -- Moses dominates as much as 15 percent of the entire Christian Bible, is a towering figure in the Hebrew Torah, and appears, by name, 136 times in the Koran -- more than any other prophet.

He is the baby who escaped death in a purge of newborns by floating in a little basket of reeds on the Nile, the young man who, raised in the midst of Egypt's royalty, took side with the Hebrew slaves. The leader who brought 2 million Hebrews out of bondage on the road to redemption and emancipation. The lawgiver who brought down, to a world filled with idols, the Ten Commandments and declared that God is one. The witness of extraordinary events: the devastating plagues, the burning bush, the parted sea, manna and dry rocks flowing with water. The intercessor between God and man, who died at the age of 120 never having entered the Promised Land.

Although Moses remains a universal symbol of liberation, leadership and law, immortalized by Michelangelo, archaeologists and biblical critics argue that there is no direct evidence for his existence.

Some details of his life, such as him as a baby floating on a basket in the Nile, appear to originate from earlier legends.Herod

The ruler of the kingdom of Judea, consisting mostly of Jerusalem and present-day southern Israel from 37 BC to 4 BC, King Herod is the Bible's bloodiest tyrant.

Known for extensive building throughout the Holy Land -- he rebuilt and expanded the Second Temple in Jerusalem, the desert fortress of Masada, as well as the port city of Caesarea and the Herodium, where he is believed to have been buried -- Herod is described as a bloodthirsty megalomaniac who killed three of his sons, executed one of his 10 wives and ordered the killing of every single male child under two in his kingdom in the attempt to destroy the infant Jesus.

Indeed, the Jewish first-century historian Josephus Flavius gave a glimpse of Herod’s methods as he described how the sick king ordered several members of the local Jewish aristocracy to be executed on his death, so that his passing would be widely and genuinely mourned.

However, there is no record, apart from Matthew's Gospel, that his most brutal act, the Massacre of the Innocents, really occurred.

“The notion persists that he was a ‘Jewish King’, persecuting ‘Jesus’ -- even Jews themselves have come to believe it so powerful is the literature and, just as Christians, so thin their real historical knowledge,” Robert Eisenman, Professor of Middle East Religions, Archaeology, and Islamic Law and Director of the Institute for the Study of Judaeo-Christian Origins at California State University Long Beach, told Discovery News.

Indeed, Herod wasn’t a "Jewish" King as is commonly thought. He came from an Idumaean (Edomite) family on his father's side and his mother was an Arab woman from Petra.

“Being ‘King of the Jews’ did not mean being ‘a Jewish King.’ It was a Roman Title and Herod himself was a poly-religionist, building different shrines for different religious groups he wish to endear himself to all over the Roman Mediterranean. The Jews paid dearly for his ambitions, as they are still paying for his reputation today,” Eisenman said.

Birth of Jesus

The story of the birth of Jesus of Nazareth, starting from Mary's virginal conception to the arrival of the wise men visiting the infant in the Bethlehem stable, continues to be the subject of scholarly debate over its historical accuracy.

The Bible itself is filled with contradictions.

According to the Gospel of Matthew, Jesus was born when Herod was king in Judea. But history records Herod's death in 4 BC -- full four years before Jesus was actually born. According to the Gospel of Luke, Jesus was born when Quirinius was governor of Syria. But historical accounts state that he didn't become governor until 6 or 7 BC -- again raising anachronistic objections.

While Luke reports that Mary and Joseph lived in Nazareth and moved to Bethlehem, where Jesus was born in a stable, Matthew accounts they lived in Bethlehem and moved to Nazareth after Jesus’ birth.